If one species had to be chosen to preserve and restore, perhaps it should be cottonwood. Cottonwood-willow forests, where they exist and are healthy, indicated the presence of a viable riparian area, which is in turn the key to conserving great proportions of our native species. A reflection of the dire status of our riparian systems is that the Sonoran cottonwood-willow and Sonoran mesquite-cottonwood forests.

With the passage of the Federal Endangered Species Act in 1973, the stage was set for a confrontation between urban development and the provisions of Federal Law. Language was amended to the Act that established standards that a plan would have to meet before the Fish and Wildlife Service could approve it and issue a permit for the take of a listed species. In those jurisdictions that have adopted this approach, conservation of natural resources is no longer an afterthought but a major element that has to be considered during the regular land use permitting process.